The invention relates to an apparatus for inserting spokes into holes of a hub flange according to the preamble of claim 1.
Such an apparatus is known from EP A 0424050. The disadvantage of the known apparatus is that the spoke is not guided sufficiently accurately with respect to the ejection opening. The objective of the spring valve that can be seen in the known apparatus is that it gives the air flow a high velocity when ejecting the spoke and the spring valve does not rest against the spoke, allowing the same to assume different positions with respect to the ejection opening. There is very little play around the spoke in the hole of the hub flange, for instance, less than 0.5 mm so that, due to the play of the spoke in the ejection opening, positioning of the spoke is not sufficiently accurate, with the result that the spoke may strike the rim of the hole or that the thread on the shaft of the spoke sometimes catches on the rim of the hole, causing defects.
In order to eliminate this drawback the apparatus is embodied in accordance with the following specification.
An alternative embodiment prevents the spokes falling into and being caught in the spoke holder from jamming against the spoke guiding means if they are somewhat bent, even though they are unable to rotate around their longitudinal axis.
An alternative embodiment requires no active control for the pressing means. Another alternative embodiment allows the spoke to be supplied head down so that after insertion the spokes fall down with the shaft. The result is that the spokes, after insertion, hang down so that they will not jam and cause defects while being rotated in the hub support.
Another embodiment allows for sufficient space to catch the spokes, while they are unable to rotate in the spoke channel. In this embodiment, the spoke channel comprises dimensions of approximately 5 mm and approximately 8 mm. In another embodiment the spoke channel is closed at four sides during insertion, so that the spoke is guided properly. In the apparatuses of the prior art it is not possible to bring the ejection openings close to the hub flange in front of the holes through which the spokes have to be inserted outward from between the hub flanges. The spoke holders then jam against the flanges if the direction of insertion is more or less in the longitudinal direction of the hole in the hub flange, which is necessary if there is little play between a spoke and a hole in the hub flange.
In order to avoid the above drawback, the apparatus in accordance with a further improvement is embodied to insert spokes over a distance of at least 40 mm from the ejection opening, the spoke guiding means are formed by a wall which, at the side facing the hub, has a thickness of less than approximately 1.0 mm. This makes it possible to insert the spoke close to a hub flange into a hole in the overlying flange.
Another embodiment allows the ejection opening to be moved to the hole in the overlying flange in a straight line, allowing the spoke holder to be moved to the hub flange.
In accordance with a further improvement of the invention, the apparatus is embodied wherein a spoke turner is provided between the spoke sorting means and the spoke holder, for turning the head of a separated spoke downward. To insure that the spoke falls properly after insertion, it is essential that the head points down. This can be guaranteed by positioning the spoke with the head pointing downward.
In accordance with one embodiment the apparatus is embodied so that the spoke turner comprises catching means for a separated spoke, and alignment means capable of moving to the head of the caught spoke. This is a simple manner of positioning the spoke in the desired manner.
During loading the hub rotates, always positioning the next hole in front of the inserter, with the inserted spokes projecting from the holes in the hub flanges. In the prior art apparatus these spokes may come into contact with the hubs that are presented, which may cause a defect.
In order to avoid the above-mentioned drawback, the apparatus is embodied so that the hubs are conveyed to the hub support by conveyor means comprising a gripper. After the loaded hub is removed, the hubs can be conveyed conveniently by using a gripper.
In another embodiment the hub is unambiguously positioned in the axial direction irrespective of the width of the hub, thereby facilitating the positioning on the hub support.
In the prior art apparatus where the rotation means comprise a drive roll pushing against the hub flange, the spokes are inserted at the top side of the hub flanges. This results in some of the spokes falling onto the hub axle which means that the spokes may become jumbled and cause a defect.
In accordance with one embodiment the apparatus is embodied so that the rotation means comprise a drive roll pushing against the hub flange wherein for every hub flange the spoke guide means, the ejector openings and the respective sensors are directed at a location hole which lies on a horizontal plane through the hub axle, and the drive roll pushes against the hub flange above said horizontal plane. This embodiment allows the spokes to fall freely without touching the hub or the drive roll.
The drive roll pushes against the hub flange in a direction of approximately 45 to 75 degrees in relation to the horizontal plane.
In yet another embodiment the hub support can be simply adjusted for a hub of different dimensions, while hubs of the same dimensions can be fitted quickly into the apparatus.
Still another embodiment allows simple adjustment to another hub dimension by bringing both adjustable spoke inserters together onto the correct position.
The invention also comprises a method relating to the method known from EP A 0424050. The disadvantage with the known apparatus is that it is not always certain that the spoke, after it has been inserted, will hang head down so that the bend in the shaft can turn through the hole in the hub flange, allowing the shaft to fall through. If the head points upward, it will rest on the hub flange and the weight of the shaft will pull the bend out of the hub flange with the result that the shaft will not fall through.
In order to avoid the above-mentioned drawback, insertion is carried out in accordance with the characterizing part of claim 17. Guiding the spoke""s downward pointing head until the spoke""s shaft, after having been inserted, can fall through at the other side of the hub flange, will prevent the head from turning upward, which would hinder the shaft""s falling through.
In the prior art apparatus, after a spoke has been inserted into a hole of the first hub flange a next hole in the second hub flange is brought before the insertion position by rotating the hub flange in such a way as to move the inserted spoke downward. In this way the inserted spokes do not interfere with holes whose positions have still to be detected. If, due to loose flanges or manufacturing faults the holes in the two flanges are not staggered in the usual way, but are in the direction of rotation positioned close together, then the next hole is not easily detectable.
In order to avoid this drawback the method is carried out in accordance with claim 18. This method ensures that the next hole is found, even if it is at the same rotation position as the loaded hole in the other hub flange.